tls: yield downstream read retries to the event loop

.github/workflows/call-windows-unit-tests.yaml

@@ -37,18 +37,21 @@ jobs:
           - name: "Windows 32bit"
             arch: x86
             cmake_additional_opt: ""
+            runtime_tests: "Off"
             vcpkg_triplet: x86-windows-static
             cmake_version: "3.31.6"
             os: windows-latest
           - name: "Windows 64bit"
             arch: x64
             cmake_additional_opt: ""
+            runtime_tests: "On"
             vcpkg_triplet: x64-windows-static
             cmake_version: "3.31.6"
             os: windows-latest
           - name: "Windows 64bit (Arm64)"
             arch: amd64_arm64
             cmake_additional_opt: "-DCMAKE_SYSTEM_NAME=Windows -DCMAKE_SYSTEM_VERSION=10.0 -DCMAKE_SYSTEM_PROCESSOR=ARM64"
+            runtime_tests: "Off"
             vcpkg_triplet: arm64-windows-static
             cmake_version: "3.31.6"
             os: windows-11-arm
@@ -207,13 +210,15 @@ jobs:
         run: |
           cmake -G "NMake Makefiles" `
             -D FLB_TESTS_INTERNAL=On `
+            -D FLB_TESTS_RUNTIME=${{ matrix.config.runtime_tests }} `
             -D FLB_NIGHTLY_BUILD='${{ inputs.unstable }}' `
             -D OPENSSL_ROOT_DIR='C:\vcpkg\installed\${{ matrix.config.vcpkg_triplet }}' `
             ${{ matrix.config.cmake_additional_opt }} `
             -D FLB_LIBYAML_DIR='C:\vcpkg\installed\${{ matrix.config.vcpkg_triplet }}' `
             -D FLB_WITHOUT_flb-rt-out_elasticsearch=On `
             -D FLB_WITHOUT_flb-rt-out_td=On `
             -D FLB_WITHOUT_flb-rt-out_forward=On `
+            -D FLB_WITHOUT_flb-rt-filter_rewrite_tag=On `
             -D FLB_WITHOUT_flb-rt-in_disk=On `
             -D FLB_WITHOUT_flb-rt-in_proc=On `
             -D FLB_WITHOUT_flb-it-unit_sizes=On `
@@ -247,6 +252,12 @@ jobs:
 
       - name: Run unit tests for Fluent Bit packages (x86, x64, and ARM64)
         run: |
-            ctest --build-run-dir "$PWD" --output-on-failure
+            $nparallel = 1
+            if ('${{ matrix.config.runtime_tests }}' -eq 'On') {
+              $nparallel = [Math]::Min([Environment]::ProcessorCount, 8)
+            }
+
+            Write-Host "Running CTest with parallel level $nparallel"
+            ctest --parallel $nparallel --build-run-dir "$PWD" --output-on-failure
         shell: pwsh
         working-directory: build

.github/workflows/cron-scorecards-analysis.yaml

@@ -46,7 +46,7 @@ jobs:
 
       # Upload the results to GitHub's code scanning dashboard.
       - name: "Upload to code-scanning"
-        uses: github/codeql-action/upload-sarif@54f647b7e1bb85c95cddabcd46b0c578ec92bc1a # v4.36.3
+        uses: github/codeql-action/upload-sarif@7188fc363630916deb702c7fdcf4e481b751f97a # v4.37.1
         with:
           sarif_file: results.sarif
           category: ossf-scorecard

.github/workflows/cron-stale.yaml

@@ -12,7 +12,7 @@ jobs:
     name: Mark stale
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/stale@eb5cf3af3ac0a1aa4c9c45633dd1ae542a27a899 # v10.3.0
+      - uses: actions/stale@1e223db275d687790206a7acac4d1a11bd6fe629 # v10.4.0
         with:
           repo-token: ${{ secrets.GITHUB_TOKEN }}
           stale-issue-message: 'This issue is stale because it has been open 90 days with no activity. Remove stale label or comment or this will be closed in 5 days. Maintainers can add the `exempt-stale` label.'

.github/workflows/pr-fuzz.yaml

@@ -36,7 +36,7 @@ jobs:
         path: ./out/artifacts
     - name: Upload Sarif
       if: always() && steps.build.outcome == 'success'
-      uses: github/codeql-action/upload-sarif@54f647b7e1bb85c95cddabcd46b0c578ec92bc1a # v4.36.3
+      uses: github/codeql-action/upload-sarif@7188fc363630916deb702c7fdcf4e481b751f97a # v4.37.1
       with:
         # Path to SARIF file relative to the root of the repository
         sarif_file: cifuzz-sarif/results.sarif

.github/workflows/staging-release.yaml

@@ -806,7 +806,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Release 2.0 - not latest
-        uses: softprops/action-gh-release@718ea10b132b3b2eba29c1007bb80653f286566b # v3.0.1
+        uses: softprops/action-gh-release@3d0d9888cb7fd7b750713d6e236d1fcb99157228 # v3.0.2
         if: startsWith(inputs.version, '2.0')
         with:
           body: "https://fluentbit.io/announcements/v${{ inputs.version }}/"
@@ -818,7 +818,7 @@ jobs:
           make_latest: false
 
       - name: Release 2.1 - not latest
-        uses: softprops/action-gh-release@718ea10b132b3b2eba29c1007bb80653f286566b # v3.0.1
+        uses: softprops/action-gh-release@3d0d9888cb7fd7b750713d6e236d1fcb99157228 # v3.0.2
         if: startsWith(inputs.version, '2.1')
         with:
           body: "https://fluentbit.io/announcements/v${{ inputs.version }}/"
@@ -830,7 +830,7 @@ jobs:
           make_latest: false
 
       - name: Release 3.0 - not latest
-        uses: softprops/action-gh-release@718ea10b132b3b2eba29c1007bb80653f286566b # v3.0.1
+        uses: softprops/action-gh-release@3d0d9888cb7fd7b750713d6e236d1fcb99157228 # v3.0.2
         if: startsWith(inputs.version, '3.0')
         with:
           body: "https://fluentbit.io/announcements/v${{ inputs.version }}/"
@@ -842,7 +842,7 @@ jobs:
           make_latest: false
 
       - name: Release 3.1 - not latest
-        uses: softprops/action-gh-release@718ea10b132b3b2eba29c1007bb80653f286566b # v3.0.1
+        uses: softprops/action-gh-release@3d0d9888cb7fd7b750713d6e236d1fcb99157228 # v3.0.2
         if: startsWith(inputs.version, '3.1')
         with:
           body: "https://fluentbit.io/announcements/v${{ inputs.version }}/"
@@ -854,7 +854,7 @@ jobs:
           make_latest: false
 
       - name: Release 3.2 - not latest
-        uses: softprops/action-gh-release@718ea10b132b3b2eba29c1007bb80653f286566b # v3.0.1
+        uses: softprops/action-gh-release@3d0d9888cb7fd7b750713d6e236d1fcb99157228 # v3.0.2
         if: startsWith(inputs.version, '3.2')
         with:
           body: "https://fluentbit.io/announcements/v${{ inputs.version }}/"
@@ -866,7 +866,7 @@ jobs:
           make_latest: false
 
       - name: Release 4.0 - not latest
-        uses: softprops/action-gh-release@718ea10b132b3b2eba29c1007bb80653f286566b # v3.0.1
+        uses: softprops/action-gh-release@3d0d9888cb7fd7b750713d6e236d1fcb99157228 # v3.0.2
         if: startsWith(inputs.version, '4.0')
         with:
           body: "https://fluentbit.io/announcements/v${{ inputs.version }}/"
@@ -878,7 +878,7 @@ jobs:
           make_latest: false
 
       - name: Release 4.1 - not latest
-        uses: softprops/action-gh-release@718ea10b132b3b2eba29c1007bb80653f286566b # v3.0.1
+        uses: softprops/action-gh-release@3d0d9888cb7fd7b750713d6e236d1fcb99157228 # v3.0.2
         if: startsWith(inputs.version, '4.1')
         with:
           body: "https://fluentbit.io/announcements/v${{ inputs.version }}/"
@@ -890,7 +890,7 @@ jobs:
           make_latest: false
 
       - name: Release 4.2 - not latest
-        uses: softprops/action-gh-release@718ea10b132b3b2eba29c1007bb80653f286566b # v3.0.1
+        uses: softprops/action-gh-release@3d0d9888cb7fd7b750713d6e236d1fcb99157228 # v3.0.2
         if: startsWith(inputs.version, '4.2')
         with:
           body: "https://fluentbit.io/announcements/v${{ inputs.version }}/"
@@ -902,7 +902,7 @@ jobs:
           make_latest: false
 
       - name: Release 5.0 and latest
-        uses: softprops/action-gh-release@718ea10b132b3b2eba29c1007bb80653f286566b # v3.0.1
+        uses: softprops/action-gh-release@3d0d9888cb7fd7b750713d6e236d1fcb99157228 # v3.0.2
         if: startsWith(inputs.version, '5.0')
         with:
           body: "https://fluentbit.io/announcements/v${{ inputs.version }}/"

.github/workflows/unit-tests.yaml

@@ -22,6 +22,7 @@ on:
       - 'examples/**'
     branches:
       - master
+      - 5.0
       - 4.2
       - 4.1
       - 4.0

AGENTS.md

@@ -2,10 +2,17 @@
 
 ## Preferred Commands
 - Configure: `cmake -S . -B build -DFLB_TESTS_RUNTIME=On -DFLB_TESTS_INTERNAL=On`
+- Configure on Windows:
+  `cmake -S . -B build -DFLB_TESTS_RUNTIME=On -DFLB_TESTS_INTERNAL=On`
 - Build: `cmake --build build -j8`
 - Test: `ctest --test-dir build --output-on-failure`
 - Prefer targeted tests with `ctest --test-dir build -R <name> --output-on-failure`
   when the affected area is known, because the full enabled suite can be slow.
+- Windows supports building and running runtime tests. Prefer focused
+  `flb-rt-*` targets or CTest matches because the full runtime suite can be
+  slow. The GitHub Actions unit-test workflow enables runtime execution only
+  for x64 to control CI running time. Do not apply that CI-only restriction to
+  local agents or AI cloud builds.
 - Run a focused integration test with
   `ctest --test-dir build -R flb-it-opentelemetry --output-on-failure`
 - Run the in-tree Python integration suite with:
@@ -29,8 +36,22 @@ Fluent Bit is a C/C++ monorepo built with CMake.
 
 Keep changes scoped: plugin logic in its plugin directory, shared behavior in `src/` or `lib/`.
 
+## Bundled Library Changes
+- Treat `lib/` as bundled third-party or separately maintained code unless the
+  specific path is clearly Fluent Bit-owned.
+- Before editing bundled library code, ask for explicit user confirmation. If
+  the agent environment supports confirmation popups, use one; otherwise ask in
+  chat before writing files.
+- Prefer changes that can be sent upstream as a focused patch. Keep bundled
+  library patches isolated from Fluent Bit glue code, and document the upstream
+  project/path in the close-out.
+- Do not mix bundled library edits with unrelated Fluent Bit core, plugin,
+  documentation, or test changes in the same commit unless the user explicitly
+  asks for that structure.
+
 ## Build, Test, and Development Commands
-- `cmake -S . -B build -DFLB_TESTS_RUNTIME=On -DFLB_TESTS_INTERNAL=On`: configure with runtime + internal tests.
+- `cmake -S . -B build -DFLB_TESTS_RUNTIME=On -DFLB_TESTS_INTERNAL=On`:
+  configure runtime and internal tests, including on Windows.
 - `cmake --build build -j8`: compile Fluent Bit and tests.
 - `ctest --test-dir build --output-on-failure`: run enabled tests.
 - `ctest --test-dir build -R flb-it-opentelemetry --output-on-failure`: run a focused integration test.
@@ -63,6 +84,12 @@ Keep changes scoped: plugin logic in its plugin directory, shared behavior in `s
 - Add or update tests for behavior changes, especially protocol parsing and encoder/decoder paths.
 - Prefer targeted tests close to the changed module (`tests/internal`, plugin runtime tests).
 - Prefer focused `ctest -R ...` runs or specific test binaries when the touched area is known.
+- Windows supports `tests/runtime`, `flb-rt-*` targets, and runtime CTest
+  matches. Configure with `-DFLB_TESTS_RUNTIME=On` and run applicable focused
+  runtime coverage. In `.github/workflows/call-windows-unit-tests.yaml`, keep
+  runtime execution disabled for x86 and ARM64 unless the workflow scope
+  explicitly changes; that exclusion controls GitHub Actions running time only.
+  It does not apply to local agents or AI cloud builds.
 - Use `tests/integration` when validating end-to-end plugin behavior, network
   protocols, downstream request generation, or local fake-server interactions
   that are awkward to cover in `ctest` binaries alone.
@@ -81,6 +108,9 @@ Keep changes scoped: plugin logic in its plugin directory, shared behavior in `s
   `cmake --build build -j8`
   `tests/integration/.venv/bin/python -m pytest <focused-scenario> -q`
   `VALGRIND=1 VALGRIND_STRICT=1 tests/integration/.venv/bin/python -m pytest <focused-scenario> -q`
+- On Windows, use the same `-DFLB_TESTS_RUNTIME=On` configuration and run
+  relevant focused runtime cases. Valgrind is normally unavailable on Windows;
+  report that exact blocker instead of conflating it with runtime-test support.
 - Run broader test coverage when changing shared lifecycle, routing, storage, or accounting code.
 - Validate both success and failure paths (invalid payloads, boundary sizes, null/missing fields).
 - You can also run specific binaries from `build/bin` (e.g., `./bin/flb-it-opentelemetry`).
@@ -167,7 +197,8 @@ Keep changes scoped: plugin logic in its plugin directory, shared behavior in `s
   path inference before choosing a commit subject. For example, changes only to
   `AGENTS.md` must use `agents:`, not `docs:`.
 - For pull-request-style validation, use full history and fetch the base branch
-  first, matching CI behavior:
+  first, matching CI behavior. This is required because the checker can fall
+  back to validating only `HEAD` when the base ref is unavailable:
   `git fetch --all --prune`
   `git fetch origin <base-branch>:origin/<base-branch>`
 - Before pushing a branch or opening/updating a PR, agents must lint the full
@@ -185,6 +216,7 @@ Keep changes scoped: plugin logic in its plugin directory, shared behavior in `s
 - Do not open issues, pull requests, or remote branches unless the user explicitly asks.
 - Do not rewrite git history, amend commits, or force-push unless the user explicitly asks.
 - Do not revert user changes outside the requested scope.
+- Do not edit bundled libraries under `lib/` without explicit confirmation.
 - Prefer minimal patches that avoid unrelated formatting or refactoring churn.
 
 ## Agent Playbook (Pipeline Architecture Primer)
@@ -255,7 +287,8 @@ Keep changes scoped: plugin logic in its plugin directory, shared behavior in `s
 
 ### Testing strategy
 - Use `tests/internal` for core lifecycle/accounting logic.
-- Use `tests/runtime` for plugin-level behavior and end-to-end semantics.
+- Use `tests/runtime` for plugin-level behavior and end-to-end semantics,
+  including Windows runtime targets supported by the active toolchain and host.
 - Add regression tests for:
   - mixed signals
   - processor drop/modify paths

CMakeLists.txt

@@ -9,8 +9,8 @@ set(CMAKE_POLICY_DEFAULT_CMP0069 NEW)
 
 # Fluent Bit Version
 set(FLB_VERSION_MAJOR  5)
-set(FLB_VERSION_MINOR  0)
-set(FLB_VERSION_PATCH  9)
+set(FLB_VERSION_MINOR  1)
+set(FLB_VERSION_PATCH  0)
 set(FLB_VERSION_STR "${FLB_VERSION_MAJOR}.${FLB_VERSION_MINOR}.${FLB_VERSION_PATCH}")
 
 set(CMAKE_POSITION_INDEPENDENT_CODE ON)
@@ -374,6 +374,7 @@ if(FLB_ALL)
   # Output plugins
   set(FLB_OUT_ES          1)
   set(FLB_OUT_FORWARD     1)
+  set(FLB_OUT_GCS         1)
   set(FLB_OUT_GELF        1)
   set(FLB_OUT_HTTP        1)
   set(FLB_OUT_NATS        1)
@@ -816,6 +817,7 @@ add_subdirectory(${FLB_PATH_LIB_JSMN})
 # Runtime Tests (filter_kubernetes) requires HTTP Server
 if(FLB_TESTS_RUNTIME)
   FLB_OPTION(FLB_HTTP_SERVER  ON)
+  FLB_OPTION(FLB_IN_EVENT_TEST ON)
 endif()
 
 # Monkey Core Library
@@ -1453,8 +1455,8 @@ if(NOT FLB_POSIX_TLS)
   check_c_source_compiles("
    __thread int a;
    int main() {
-       __tls_get_addr(0);
-       return 0;
+       a = 1;
+       return a - 1;
    }" FLB_HAVE_C_TLS)
   if(FLB_HAVE_C_TLS)
     FLB_DEFINITION(FLB_HAVE_C_TLS)
@@ -1530,6 +1532,14 @@ else()
 endif()
 
 # Instruct CMake to build the Fluent Bit Core
+if(MSVC OR FLB_JEMALLOC)
+  # MSVC tests need plugin-private symbols that are not exported from fluent-bit.dll.
+  # Jemalloc must not be embedded in both the test executable and shared library.
+  set(FLB_TEST_LINK_LIBRARY fluent-bit-static)
+else()
+  set(FLB_TEST_LINK_LIBRARY fluent-bit-shared)
+endif()
+
 add_subdirectory(include)
 add_subdirectory(plugins)
 add_subdirectory(src)

MAINTENANCE.md

@@ -6,15 +6,16 @@ This document outlines the maintenance strategy and version support for Fluent B
 
 | Branch     | Version            | Status              | Maintainer                                                  | Notes                                                              |
 |------------|--------------------|---------------------|-------------------------------------------------------------|--------------------------------------------------------------------|
-| `master`   | v5.0 (development) | Active development  | [Eduardo Silva](https://github.com/edsiper)                 | All new features and bug fixes land here first                     |
-| `4.2`      | v4.2.x             | Stable              | [Eduardo Silva](https://github.com/edsiper) [Hiroshi Hatake (@cosmo0920)](https://github.com/cosmo0920) | Current stable release series. Active development and updates. May receive minor enhancements in addition to fixes.     |
+| `master`   | v5.1 (development) | Active development  | [Eduardo Silva](https://github.com/edsiper)                 | Next minor development line. All new features and bug fixes land here first |
+| `5.0`      | v5.0.x             | Stable              | [Eduardo Silva](https://github.com/edsiper) [Hiroshi Hatake (@cosmo0920)](https://github.com/cosmo0920) | Current stable release series. Receives bug fixes, security fixes, and selected low-risk backports. |
+| `4.2`      | v4.2.x             | Maintenance only    | [Eduardo Silva](https://github.com/edsiper) [Hiroshi Hatake (@cosmo0920)](https://github.com/cosmo0920) | Critical fixes and safe backports only. Maintained until **July 30, 2026** |
 | `4.1`      | v4.1.x             | Maintenance only    | [Hiroshi Hatake (@cosmo0920)](https://github.com/cosmo0920) | Critical fixes and safe backports only. Maintained until **February 28, 2026** |
 
 ---
 
 ## Maintenance Policy
 
-Active development is currently on Fluent Bit **v5.0** (tracked in the `master` branch). The **v4.2** branch is the current stable release series and receives active updates. Previous release lines enter **maintenance mode** after the next major/minor release.
+Active development is currently on the next Fluent Bit **v5.1** line (tracked in the `master` branch). The **v5.0** branch is the current stable release series and receives stable branch updates. Previous release lines enter **maintenance mode** after the next major/minor release.
 
 ### Accepted Changes for Maintenance Branches
 
@@ -26,9 +27,13 @@ Active development is currently on Fluent Bit **v5.0** (tracked in the `master`
 
 Maintenance releases continue on an as-needed basis depending on urgency and impact.
 
-### v4.2 Stable Series
+### v5.0 Stable Series
 
-**v4.2** is the current stable release series and receives active development, bug fixes, and security updates. This is the recommended version for production use.
+**v5.0** is the current stable release series and receives bug fixes, security updates, and selected low-risk backports. This is the recommended version for production use.
+
+### v4.2 Maintenance
+
+**v4.2** has entered **maintenance mode** and receives critical fixes and safe backports until **July 30, 2026** (as specified in [SECURITY.md](SECURITY.md)).
 
 ### v4.1 Maintenance
 
@@ -44,11 +49,12 @@ Maintenance releases continue on an as-needed basis depending on urgency and imp
 
 ## How to Contribute to Maintained Versions
 
-If you're submitting a fix or feature relevant to a stable or maintenance branch (v4.2 or v4.1):
+If you're submitting a fix or feature relevant to a stable or maintenance branch (v5.0, v4.2, or v4.1):
 
 - Open your PR against the `master` branch
-- Add a note in the PR or issue: `Target: v4.2` or `Target: v4.1`
+- Add a note in the PR or issue: `Target: v5.0`, `Target: v4.2`, or `Target: v4.1`
 - Tag the branch maintainer to request backport consideration:
+  - For v5.0: [@edsiper](https://github.com/edsiper) [@cosmo0920](https://github.com/cosmo0920)
   - For v4.2: [@edsiper](https://github.com/edsiper) [@cosmo0920](https://github.com/cosmo0920)
   - For v4.1: [@cosmo0920](https://github.com/cosmo0920)
 

README.md

@@ -26,7 +26,7 @@ Fluent Bit supports a wide array of platforms, including Linux, Windows, MacOS,
 ## 📌 Roadmap & Maintenance
 
 We follow a fast-paced development cycle, with major releases every 3–4 months.
-The active development branch (`master`) is currently focused on **v5.0** (development).
+The active development branch (`master`) is currently focused on **v5.1** (development).
 
 For version-specific maintenance timelines and policies, see our [MAINTENANCE.md](https://github.com/fluent/fluent-bit/blob/master/MAINTENANCE.md).
 

cmake/headers.cmake

@@ -7,6 +7,7 @@ if(NOT DEFINED FLB_PATH_ROOT_BINARY_DIR)
 endif()
 
 include_directories(
+  ${FLB_PATH_ROOT_BINARY_DIR}/generated/include
   ${FLB_PATH_ROOT_SOURCE}/include/
   ${FLB_PATH_ROOT_SOURCE}/lib/